During ten flights from March 1965 to November 1966, astronauts and ground controllers tested out the rendezvous and docking techniques that would be crucial for a successful lunar mission. They also learned more about weightlessness and its effects during longer-duration flights. When Gemini 12 splashed down on Nov. 15, 1966, NASA's bridge to the moon was complete.
Just weeks after Mercury astronaut Alan Shepard became the first American in space in May 1961, President John F. Kennedy announced the goal of sending astronauts to the moon before the end of the decade. Building on the Mercury successes, NASA soon expanded its manned space flight program to include the development of a two-man spacecraft dubbed Gemini. It would serve as the essential bridge between the first tentative steps of Mercury and the history-making lunar landings of Apollo.